I. Field of the Invention
This invention relates generally to machines for stripping materials, such as adhesive bonded floor coverings from floor surfaces, and more particularly to an improved machine of this type incorporating a novel electric motor drive system for moving the machine's cutting head in an orbital pattern and for driving its wheels and thereby allowing heavier loading of the machine's cutting head on the floor surface which improves the stripping action while reducing the work effort of the operator.
II. Discussion of the Prior Art
Back in 1979, my father was awarded U.S. Pat. No. 4,162,809 on a motorized carpet and tile stripping machine that comprised a box-like housing mounted on a pair of wheels disposed near the rear of the housing and a cutting blade projecting outwardly from the front of the housing and adapted to engage the ground beneath a floor covering that had been adhesively bonded to the floor. Supported on an upper deck of the housing was an electric motor whose output shaft was coupled to the machine's cutting head by means of an eccentric drive shaft such that the cutting head was made to move in an orbital or elliptical pattern. An elongated handle was also affixed to the upper deck of the housing and sloped rearward and upward terminating in handle grips.
When this machine was used to strip a floor covering, such as adhesively bonded carpeting from a concrete floor, the operator would first use a knife to cut the carpeting into strips. Next, the stripping machine would be placed at one end of the cut strip with its cutting head disposed in the interface between the carpeting and floor. The operator would then activate the motor to cause the cutting blade to orbitally rotate while he manually urged the machine forward by pushing against the handle.
While the machine made in accordance with the '809 patent was somewhat effective in its operation, it required a high degree of manual effort and also vibrated excessively making it somewhat difficult to control.
In my earlier U.S. Pat. No. 4,626,033, there is described an improvement I made to my father's design to make the machine easier for an operator to control. Specifically, I added a motion retainer bar assembly between the machine's frame and the cutting head's drive bar to modify the degree of eccentricity between the drive bar and the shaft of the electric drive motor. While this improvement did make the machine somewhat easier to control, vibration remains somewhat excessive and the cutting blade actuation, while separating the carpeting from the floor, left considerable adhesive residue on the floor.
In my later U.S. Pat. No. 4,963,224, I described yet another improvement that I made to the floor stripping machine to reduce vibration. I designed in a pair of OILITE.RTM. sleeve bearings and affixed a pair of guide rods to the cutting head and which fit into the sleeve bearings to thereby constrain motion of the cutting head to reciprocatory, back-and-forth movement parallel to the path of travel of the machine. While this improvement did, in fact, reduce machine vibration and prolong its useful life, minimizing its mean time to repair, no improvement was seen in the ability of the machine to remove adhesive residue from the floor following the stripping of the carpet therefrom.
The present invention comprises a still further improvement in floor stripping machines of the type described. I have found that by significantly increasing the downward force of the machine's cutting blade against the floor by drastically increasing the overall weight of the machine, the scraping action of the cutting blade when being pressed down on the floor by the weight of the machine markedly improved its ability to remove adhesive residues. Increasing the weight of the machine, however, would make it that much more difficult for an operator to push. Accordingly, I have developed a drive system for the machine in which the same motor used to drive the cutting blade also drives the machine's wheels, making it self-propelled and reducing the work effort required by the human operator.